Analysis of machine tool structure using RSM approach

Abstract

Unwanted vibration in machine tools like milling, lathe, grinding machine is one of the main problem as it affects the quality of the machined parts, tool life and noise during machining operation. Hence these unwanted vibrations are needed to be suppressed or damped out while machining. Therefore the present work concentrates and aims on study of different controllable parameter that affect the responses like vibration amplitude and roughness of machined part. The part to be machined is kept on sandwich of plates made up of polymer and composite material. The sandwich along with the part to be machined, fixed on the slotted table of horizontal milling machine. The parameters that can easily be controlled are feed, RPM of cutter, depth of cut, and number of plates that form the secondary bed material.Polymers like Polyvinyl Chloride (PVC), Polypropylene (PP) plates and composites like Glass Fiber Polyester and Glass Fiber Epoxy (GFE) plates are used in the experiments to form the sandwich (secondary bed material) on which work-piece (MS Plate) was mounted and fed to the milling cutter. Four holes are made on the specimen and the plates to ensure that the sandwich of plate including the work-piece can be bolted to the slotted table.Common up-milling operation was carried out in controlled manner. Vibration signals were recorded on the screen of phosphorous storage oscilloscope and surface roughness of machined plate was found from the Talysurf. Finite element analysis (FEA) was carried out to know the resonance frequencies at which the structure should not be excited. In the course of the FEA some important facts have come up that lead to set some of the steps of precautions during the experimentation. Response surface methodology (RSM) is used to develop the model equation for each set of plate material.